Apparatus for road construction



April 7, 1953 w. 1', DAY

APPARATUS FOR ROAD cousmucnou 4 Sheets-Sheet Filed Jan. 30. 1948 INVENTOR; Mil/AM R 0/1) m 6 N w T r A ApriI7, 1953 w. P. DAY 2,633,781

APPARATUS FOR ROAD CONSTRUCTION Filed Jan. 50. 1948 4 Sheets-Sheet 2 INVENT0R.8

WILL/AM 2 DA) ATTOQNEYS April 7, "1953 Filed Jan. 30. 1948 l II I l l l l W- P. DAY

APPARATUS FOR ROAD CONSTRUCTION 4 Sheets-Sheet 3 INVENTOR, W/LL/AM any April 7, 1953 w. P, DAY

APPARATUS FOR ROAD QOII S'IRUCTION 4 Sheets-Sheet Filed Jan. 30. 1948 INVENTOR. W/Ll/AM R DAY 1 a/al-czjy Patented Apr. 7, 1953 UNITED STATES PATENT OFFICE 3 Claims.

The present invention relates to a road working apparatus and method for impacting and keying the base materials for flexible type roads.

In building flexible type roads, of which macadam roads are one example, it is customary to form a base which includes one or more courses of relatively large aggregate with finer particles, referred to as fines, filled in the interstices between the pieces of aggregate. Heretofore this type of foundation was formed by depositing a layer of coarse aggregate along the roadway after which a heavy roller was passed thereover to key or nest the aggregate together. A layer of fines was then spread over the aggregate and the heavy roller was passed thereover to force the fines into the spaces and voids between theaggregate. Subsequent steps included the addition of a liquid or fluid binder to the road which was designed to permeate the road bed and bind the fines and aggregate. -The roller was again used to force the binder into the road. One objection to this type of road working was that the rolling action of the roller would displace or unkey the aggregate from its original repose and it would also compress the fines so that it would" be more or less diiiicult for the latter to enter the voids and form a firm nesting arrangement for the aggregate. Generally the fines would tend to form a crust at the upper portion of the road base and after the road'was completed and in use the fines would gradually settle and sift downwardly between the unsettled aggregate and thereby remove the support for the road surface.

This resulted, of course, in a deterioration of the road.

An object of the present invention is to provide a method of forming a flexible type road by which rolling of the road can be dispensed with and at the same time thorough keying and compacting of the road bed can be accomplished;

Another object of the present invention is to provide an apparatus for causing keying or nesting of the aggregate and to cause the fines and the binder to sift downwardly through the voids.

a road working apparatus capableof applying vibration to the base of a flexible road during the construction thereof so that theaggregate will be keyed together and the fines and binder will gravitate downwardly through the spaces between the aggregate and fill all voids in the base but without disturbing the keyed aggregate.

A further object of the invention is to provide a road working apparatus which is capable of applying vibrations to the road foundation in an area extending transversely of the road and which vibration can be applied to this entire area will be apparent from the following description of preferred forms of the invention, reference being made to the accompanying drawings wherein:

Fig. 1 is a side view in elevation of a road Working apparatus;

Fig. 2 is a plan view of the apparatus shown in Fig. 1;

Fig. 3 is a plan view, partly in section, of a vibratory shoe;

Fig. 4 is a side view of a vibratory shoe, certain parts of the shoe being broken away;

Fig. 5 is a view in section taken on line 55 of Fig. 3;

Fig. 6 is a fragmentary view in section of a connection between a shoe carrying arm and the traction machine;

Fig. 7 is a fragmentary view illustrating the power drive for the vibrator shoes;

Fig. .8 isa side view of a vibrator shoe illus- 1tra-ting the efiect of the shoe on a road foundaion;

Fig. 9 is a diagrammatic illustration of another form of vibratory shoe; and,

Fig. 10 is a view similar to Fig. 9 but of still another form of vibratory shoe.

Referring now to the drawings, a road working apparatus embodying my invention is shown at it. This apparatus consists, generally, of a traction machine ll having a plurality of vibratory shoes l2 individually mounted at one end thereof and arranged to contact the ground and impart vibrations thereto in a manner to be more fully described hereinafter.

The traction machine may be of any suitable construction and in th present form it consists of a frame is mounted on crawler track mechanism It. This track mechanism, parts of which are omitted from the drawing for sake of clarity, is of conventional design and it is p ed to be driven by a gasoline engine I! through a suitable gear reduction box !8, drive shaft l9 and chains 20. The tracks are individually controlled by levers 2! for steerin the machine in the usual manner well understood in the art. Preferably, the traction machine has four speeds in either direction, rangin from ten to;one hundred and forty feet 1 per minute.

Referring now to the construction of the Vibratory shoes l2, these shoes each comprise a relatively heavy shoe plate 3!; which may be approximately two feet wide and slightly longer, with the front and rear portions of'ithe'plate sloping upwardly as at 3| and terminating in upturned end walls 32. shoe to slide over the road surface witha sub.- stantial area engaging and pressing loose materials downwardly. The sloped ends als per? mit the sho to ride over projections from th road base.

The central portion of the shoe is provided with a housing 33 containing a vibrating mechanism. The housing is formed by two parallel plates 34 welded to the plate 30, the outline of the plates 36 conforming to the channel-like longitudinal sectional contour of the shoe plate 33 so that the housing will be dustproof and will be capable of retaining a body of oil therein. A pair of unbalanced wheels 36 and 37 are mounted within the housing between walls 34 on shafts 38 and 39 respectively. The. shafts 38 and 39 are journalled in roller bearings indicated at li'l so that they may turn freely and the wheel 35 and 3? are keyed to the shafts. These wheels are preferably formed of intermeshing cog wheels each having Weights 42 bolted to one side thereof. semi-cylindrical pieces of equal mass and as may be seen in Fig. 5, th wheels are meshed so that the weights are symmetrically located. Thus, twice during each revolution of the wheels the weights will exactly counterbalance one another so that the force of the unbalanced wheels will be exerted transversely of the plane of the axes of the wheels, 1. e., in a vertical direction to impart a tampingaction to the shoe. 'The positioning of the wheel axles within the housing and the positioning of the weights on the wheels are important to my invention and will be discussedin greater detail hereinafter.

A V belt pulleyfi is keyed to shaft 3& for driv-. ing the wheels by mechanism to be explained hereinafter. Preferably, the shoes contain sufficient lubricating oil sothat the wheels 36 and 31 may dip into the oil to provide lubrication for the bearings and gear teeth. Also, the housing is sealed at the bearings by plates 46 and an oil seal All is provided surrounding the shaft 3!! extending through theseal plate 45. The top of the vibrator housing is closed by plates 48 and 49, and if desired, plate 49 may be removably attached thereto. Suitable oil filling and draining plugs may be provided, none of which appear in the drawings.

The shoes ii are attached to the traction machine by arms 59, two of which are attached" to each shoe, one on each side thereof. To efiect this attachment each shoe is provided with an L-shaped bracket 52 which has a ange 53 and a portion 54 at right angles to the flange. The brackets are'attached'to the upper side of the shoe plateSU by bolts 55. The partial-1'54 is'l This will permit the These weights are preferably vided with a laterally extending stud 51, which is welded thereto, and which provides a trunnion for engagement with the arm 55}. A vibration damper is interposed between the arm 50 and the stud 5'1 and this damper is shown consisting of concentric bushings Bi! and 52' having a cylindrical rubber body 2 interposed therebetween and bonded therewith. The bushing 66 is press fitted to the stud 5i and bushin 6! ispress fitted. in an opening in the end. of the arm' 59. The rubber body es will permit some angular movement between the arm and the shoe, and to prevent undesirable torsion this angular movement is limited by a snubbing mechanism which comprises an l..-shape bracket 65 having one'section bl welded to the arm 59, and the laterally projecting section at is p Vided With p gs and a centerin cylindrical plug" iii is adapted to extend through each opening. The plugs as are formed integral with plates 78 which are bolted to the upper side of the section Two cylindrical members 72 are welded to the shoe plate 313 and the open ends are in registration with the respective centering plugs 69. The cylindrical members each have a compression spring '53 mounted therein and the upper ends of the compression springs surrounds the plugs 69. As may be seen. in Fig. 4;, as the shoe 12 tends to rotate relative to the endof arm 5a the springs 73 will resist such movement. The upper ends of the cylindrical member 72 will engage the section 66 for limiting the degree of rotation between the arm 58 and the shoes.

The arms 50 are attached to brackets which are integral with a transversely extending beam 11 of the machine frame l5. brackets include two forwardly extendingstanchions 16 to which the arms 59 are pivotally attached by'means of shaft 80. Preferably, the arms 50 are each attached to the stanchions 75 through vibration dampers and in the preferred form of connection, shown in Fig. 6, the stanchions. are provided with an opening into which is .press fitted .a damper unitconsisting of concentric sleeves Ti and 18 with a cylindrical body of rubber l9 bonded thereto. A journal shaft 89 is press. fitted into the sleeve 78. A similar damper unit is press fitted into an openingin both arms 5E The inner sleeve of the latter unit is. freely mounted to the shaft 86 to permit ,rotation of the arm about the shaft 88 for raising. and lowering ofthe shoes l2. Spacer sleeves 8| are provided between arms 50 mounted on shaft to maintain proper positioning of the shoes.

It will be seen from Fig. 1 that the shoes I 2 may beslid along the, ground by either pushing or pulling thereof by the traction machine II. It will be. noted that the arms 58 are at an angle to horizontal and in order to prevent vibration of the shoes from being conveyed tow the machine II through they arms 58, the axes of shafts 38 and 39 of the unbalanced wheels 36 and 3'! lie in a plane which extends substantially parallel to the center line of the. arms 59. This is illustrated in Fig. 5 wherein line a represents the plane. of the axes of the, shafts 38 and 39 and b represents the plane of the center lines of arms 51!. The weights 42 on the unbalanced wheels are arranged on the wheels so that one will counterbalance the other in a direction corresponding to the direction of extension of the plane a so that the vibratory movement appliedto the shoes by the unbalanced wheels will be only in the vertical direction and themaximumforces of. the vibrations will be at Each of the' right angles to the center lines of the arms 50. Thus, the principal vibratory forces will be exerted in a more or less vertical direction to give the shoes a rapid tamping action, and very little, if any such force, will be effective in a horizontal direction so that the structure of the traction machine will be unaffected by the vibrations. Any vibration in a. horizontal direction will be absorbed by the vibration damper units described hereinbefore.

The power for operating the vibratory mechanism is provided by a gasoline engine 82 mounted on the traction machine. The engine 82 is adapted to drive a jack shaft 84 by a pulley and belt drive indicated at 83 and pulleys 85 are connected to the pulleys 44 of the vibratory mechanisms through V belts 86. It has been found that good results are obtained when the pulleys 44 are driven at 2800 to 3000 R. P. M. Preferably, the shaft 84 is formed of three separable sections indicated at 84a, 84b and 840. Each of the sections is journalled in bearings 88 mounted to the beam 11 and the sections of the shaft are connected by universal joints 89. It will be seen that when it is desired to replace a V belt 86 the appropriate section of shaft 84 may be removed without disturbing the other sections of the shaft.

Preferably, an idler pulley 92 for maintaining tension on the belts 86 is adapted to ride on each of the V belts and the idler pulley is mounted on an arm 93 pivotally attached to the beam IT.

The vibratory shoes l2 may be raised from the ground by chains 95 which are mounted on drums 96. The drums 96 are mounted on a shaft 91' which is supported on uprights 98 extending from beam IT. The shaft 91 may be rotated mechanically or manually through a gear box and a chain drive.

I prefer to form the sides of the shoes I2 on a diagonal with the straight ahead direction of movement of the traction machine as is indicated in Fig. 3 wherein the line indicates the straight ahead direction of movement of the traction machine. By forming the shoes in this manner the area of ground between adjacent shoes will be passed over by a portion of at least one of the shoes as is illustrated in Fig. 3 wherein the dotted lines indicate a shoe adjacent the shoe shown in full lines. Thus, as the machine passes along a road bed the surfaces of the shoes will engage the entire area the width of the machine although the shoes are separated from one another by a slight space.

When constructed in the manner described, each of the shoes l2 will weigh 250 to 300 pounds and will have a road contacting surface of approximately 300 square inches. Also, more or fewer shoes may be employed in one apparatus rather than six, as shown in the present embodiment. In one form of the machine which has been successfully operated with six shoes, the total width of the line of shoes is 12 feet 6 inches, so that one-half of a 24 foot road, which is the usual two lane width, can be worked at one time.

In building a flexible road, coarse aggregate,

such as slag or stone, is first'laid on the road bed five or more inches deep, for example, and shaped to grade after which the apparatus I0 is passed thereover several times. The shoes l2 vibrate and tamp the aggregate so that the latter is nested or keyed together with maximum surface contact between the individual aggregates. Sand or screening fines is then scattered over this surface two or three inches deep, as is shown at the right hand side of Fig. 8 wherein A represents the aggregate and F is the sand or fines. The apparatus is then passed over this surface with the shoes l2 in the lowered position and, as may be seen in Fig. 8, the shoes will press downwardly on the fines and while vibrating in a vertical direction and effecting a tamping at a rapid rate, the fines and aggregate will be vibrated and tapped so that the fines will sift downwardly through the aggregate and completely fill the voids in this base. The voids shown in the drawings are exaggerated for better illustration. If desired, the machine may make two to three passes over this surface to insure thorough filling of the road base with the fines and additional layers of aggregate and fines may be treated in a similar manner. By sliding the vertically vibrated shoes on the road base surface, the material forming the base is tamped and vibrated into a natural repose, thereby providing the most substantial base possible. A suitable fluid binder, known in the art as a grout may then be applied to the surface of the road bed and the apparatus passed over this material which, by the vibration, expedites and promotes the penetration of the grout into'the road bed to bind the aggregate and fines. The grout may consist of screenings, water and cement, for example. By applying the compacting force through a sliding surface rather than a line contact, as in rolling, there is no tendency to displace the keyed aggregate by passage of the apparatus thereover. In practice it has been found that by my invention, although the voids between the coarse aggregate are less than those in a roller compacted bed, more fines are sifted into the bed than by the well known roller method so that a more compact and firm road structure is provided. This compacting is so efficient that one roadway, which was opened to heavy traffic prior to the application of the binder course, withstood the traific and no displacement or damage to the road bed could be observed.

By providing a plurality of individually suspended shoes of relatively narrow width as compared to the width Of the road, substantially the entire surface of the road over which the apparatus passes will be treated although the road may have a substantial crown contour and although there may be high and low spots in the road.

In some instances it may be desirable to impart a gyratory vibration to the shoes l2 in addition to the vertical vibration provided by the unbalanced wheels 36 and 31 for imparting slight lateral vibration to the road material to promote the sifting of the fines into the voids. For example, I have found it desirable to provide a third unbalanced wheel which is preferably mounted in the housing 33 similarly to the. wheels 36 and 31. Referring to Fig. 9, such auxiliary unbalanced wheel is indicated at Iill and this wheel consists of a cog wheel one-half the diameter of wheel 31 and in mesh with the latter. The wheel I01 is journalled on an axle 102 which is journalled in bearings formed in the walls 34 of the housing. A weight W3 is attached to the wheel l0l and this weight is preferably at to the corresponding weights 42 of wheels 36 and 3?. Thus, it will be seen that wheel it! will rotate at twice the speed of wheels 36 and 3! and the Weight I03 will always be out of phase with weights 42 so that a separate gyratory vibration in a vertical plane extending longitudinally of the shoe will be imparted to the shoe. The weight I03 will, of course, be somewhat lighter than the weights 42 so that they will not affect the traction machine,

In the event it is desirable to produce a greater tamping vibration another set of unbalanced wheels may be added to the housing 33 as is illustrated in Fig. 10. In Fig. a set of unbalanced wheels 135. and I3! are mounted in the housing in mesh with wheels 36 and 37 respectively. Each of the wheels I36 and13! are provided with weights 142 which are of equalmass and similar to the weights 42. The weights [42 are positioned on their respective wheels so that they will oppose one another in the same direction which the weights 42 oppose one another and the vibration set up by the wheels I36 and 137 will be confined to the same vertical direction as the vibration set up by wheels 39 and 37. It will be obvious that if additional tamping power is desired more sets f unbalanced wheels can be added.

It will be understood that the weights 12 may be increased in mass provided they do not overtax the bearings. The extra sets of wheels are added when the bearings 40 are carrying a maximum load.

Thus, by my invention, I have provided an apparatus and method for preparing the base of a flexible road which will positively cause a filling of all voids and crevices in the base and which will cause the aggregate of the base to seek their natural repose whereby the base will have more stability than has heretofore been possible with the known machines and methods of forming road bases. Although I have described several forms of embodiments of the invention, it is to be understood that other forms might be utilized, all falling Within the scope of the claims which follow.

Iclaim:

l. A road working apparatus comprising ashoe structure having a bottom surface sloping upwardly at one end for sliding. on the surface of a road bed; mechanism mounted on the shoe for vibrating the shoe princpally in a. direction normal to the road engaging surface of the shoe, said mechanism comprising two like unbalanced wheels rotating on parallel axes at the same speed in opposite senses and having the weights thereof symmetrically located so that the forces created by rotation of the wheels will be opposed and balanced in a direction longitudinal of the shoe; a third and lighter unbalanced wheel mounted to the shoe on a shaft parallel to the shafts of said two unbalanced wheels, the shaft of said third wheel being displaced from the center of gravity of said shoe, and the off-center weight of said third unbalanced wheel being rotationally displaced relative to the corresponding positions of the off-center weights of said two unbalanced wheels; and driving means for said unbalanced wheels, including means for rotating the said third unbalanced wheel at a higher rate than that of the said two unbalanced wheels.

2. A road working apparatus comprising a traction machine; a shoe structure having a surface adapted to slide along the ground; an arm pivoted to the machine for mounting the shoe to the machine for movement in a plane longitudinal and vertical relative to the machine, the center line of said arm being inclined relative to the ground when in operating position with the said surface of the shoe structure horizontally disposed 'in contact with the ground; means securing said shoe structure in substantially fixed relationship to said arm; a pair of similar eccentrically weighted wheels mounted to the shoe and rotated at equal speeds in opposite senses by parallel shafts, the axes of said shafts being in a common plane which is substantially parallel to a plane defined by the center line of said arm when in normal operating position and a horizontal line perpendicular to said center line, and the eccentric weights of said wheels being. positioned rotationally relative to each other to substantially counterbalance one another in a direction parallel to the defined plane, whereby when the wheels are rotated at high speeds the resultant of the reaction force components developed by the eccentrically weighted wheels acts in a direction substantially normal to the defined plane; and means for driving the unbalanced wheels.

3. A road working apparatus comprising a traction machine; a shoe structure having a surface adapted to slide along the ground; an arm pivoted to the machine for mounting the shoe to the machine for movement in a plane longitudi nal and vertical relative to the machine, the center line of said arm being inclined relative to'the ground when in normal operatin position with the said surface of the shoe structure horizontally disposed in contact with the ground; means securing said shoe structure in substantially. fixed relation to said arm, said means including a shock absorbing element adapted to absorb from the shoe structure shock force components directed parallel to the center line of said arm; a pair of similar eccentricaliy weighted wheels mounted to the shoe and rotated at equal speeds in opposite senses by parallel shafts, the axes of said shafts being in a common plane which is substantially parallel to a plane defined by the center line of said arm when in normal operating position and a horizontal line perpendicular to said center line, and the eccentric Weights of said wheels being positioned rotationally relative to each other substantially to counter-balance one another in a direction parallel to the defined plane, whereby when the wheels are rotated at high speeds the resultant of the reaction force components developed by the eccentrically weighted wheels acts in a direction substantially normal to the defined plane; and means for driving the unbalanced wheels.

\NILLIAM P. DAY.

REFERENCES CITED The following references are of record in the file of this patent:

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